1. Field of the Invention
This invention relates to an outside light source display for black and white and/or colour visualization of graphic or alphanumerical data. The display has been particularly designed for an outdoor use utilizing sunlight as a light source, but it can work as well with artificial light by night and indoor. Also, the invention, utilizing pixel matrix panels, has a modular structure, thus covering a wide range of dimensions according to each particular need, from the shop to the stadium.
2. Description of the Prior Art
As it is known, display apparatuses divide into two main families according to where the light source is. Displays with an internal light source can be those using a matrix of LEDs or of incandescent lamps, or those utilizing a matrix of video monitors each showing a portion of the whole image. They both are rather expensive and require a high power consumption of many kWatts per square meter. The display apparatuses utilizing an outside light source can be represented by the common display used in airports and/or stations to give passangers the required information about leaving/arriving times etc. The messages are formed by rotation of a number of tesseras, each mounted by one of its sides on a support rod as sheets in a book. These displays do not require a high power consumption and are quite resistant, but they can show only a number of predetermined messages and images. Moreover they must be kept free from dust, thus limiting their use outside.
Another apparatus utilizing an outside light source is a matrix based display, each matrix comprising a number of plaques or cubes with differently coloured faces which are magnetically or mechanically rotated. Also this display is affected by dust, even if it has a transparent external surface: the dust accumulated on the cube faces has to be cleaned away to restore the original colours brightness. Both these two latter displays are rather economical and they can preserve the message also during a power failure, but their use outdoor is limited by their bad resistance to varying weather, they are not flexible enough, and the ratio of representative surface versus total surface is too low. Thus the need remains of a display apparatus which: utilizes pixels matrix panels, where the pixels have dimensions going from about 5 mm to about 50 mm. and can have at least 3 colours plus black and white; is weather resistant and without openings, so that it can easily be washed; has a representative efficiency which is more than 80%; can preserve the message also during a power failure; requires a low capacity, of about 50 watts per square meter; has a modular structure, where each module is easily replaceable; and utilizes an outside light source.